from rest_framework import serializers
from goods.models import SKU
from django_redis import get_redis_connection
from rest_framework_jwt.settings import api_settings
from celery_tasks.email.tasks import send_verify_email
import re

from users.models import User, Address

class EmailSerializer(serializers.ModelSerializer):
    """
    邮箱序列化器
    """
    class Meta:
        model = User
        fields = ('id', 'email')
        extra_kwargs = {
            'email': {
                'required': True
            }
        }

    def update(self, instance, validated_data):
        email = validated_data['email']
        instance.email = email
        instance.save()

        # 生成验证链接
        verify_url = instance.generate_verify_email_url()
        # 发送验证邮件
        send_verify_email.delay(email, verify_url)
        return instance


class UserDetailSerializer(serializers.ModelSerializer):
    """用户详细信息序列化器"""
    class Meta:
        model = User
        # 只有字段的输出，没有输入
        fields = ('id', 'username', 'mobile', 'email', 'email_active')


class CreateUserSerializer(serializers.ModelSerializer):
    """
    创建用户序列化器
    """
    # 只输出，用于注册前辅助校验，不会去响应这三个字段，write_only=True
    password2 = serializers.CharField(label='确认密码', write_only=True)
    sms_code = serializers.CharField(label='短信验证码', write_only=True)
    allow = serializers.CharField(label='同意协议', write_only=True)

    # 输出
    token = serializers.CharField(label='登录状态token', read_only=True)  # 增加token字段

    class Meta:
        model = User
        # 指定要校验的字段
        # password2 sms_code allow 只负责输入
        # id username password mobile 可以负责输出
        fields = ('id', 'username', 'password', 'password2', 'sms_code', 'mobile', 'allow', 'token')
        # 对模型中没有直接进行校验的字段，进行再校验
        extra_kwargs = {
            'username': {
                'min_length': 5,
                'max_length': 20,
                'error_messages': {
                    'min_length': '仅允许5-20个字符的用户名',
                    'max_length': '仅允许5-20个字符的用户名',
                }
            },
            'password': {
                'write_only': True,
                'min_length': 8,
                'max_length': 20,
                'error_messages': {
                    'min_length': '仅允许8-20个字符的密码',
                    'max_length': '仅允许8-20个字符的密码',
                }
            }
        }

    def validate_mobile(self, value):
        """验证手机号"""
        if not re.match(r'^1[3-9]\d{9}$', value):
            raise serializers.ValidationError('手机号格式错误')
        return value

    def validate_allow(self, value):
        """检验用户是否同意协议"""
        if value != 'true':
            raise serializers.ValidationError('请同意用户协议')
        return value

    def validate(self, data):
        # 判断两次密码
        if data['password'] != data['password2']:
            raise serializers.ValidationError('两次密码不一致')

        # 判断短信验证码
        redis_conn = get_redis_connection('verify_codes')
        mobile = data['mobile']
        real_sms_code = redis_conn.get('sms_%s' % mobile)
        if real_sms_code is None:
            raise serializers.ValidationError('无效的短信验证码')
        if data['sms_code'] != real_sms_code.decode():
            raise serializers.ValidationError('短信验证码错误')

        return data

    def create(self, validated_data):
        """
        创建用户
        """
        # 移除数据库模型类中不存在的属性
        del validated_data['password2']
        del validated_data['sms_code']
        del validated_data['allow']
        user = super().create(validated_data)

        # 调用django的认证系统加密密码
        user.set_password(validated_data['password'])
        user.save()

        # 生成JWT——token:在校验通过，保存完user数据之后，响应user之前，生成token,并响应到浏览器
        jwt_payload_handler = api_settings.JWT_PAYLOAD_HANDLER
        jwt_encode_handler = api_settings.JWT_ENCODE_HANDLER

        payload = jwt_payload_handler(user)
        token = jwt_encode_handler(payload)

        # 将token绑定到user
        user.token = token

        return user



class UserAddressSerializer(serializers.ModelSerializer):
    """
    用户地址序列化器
    """
    province = serializers.StringRelatedField(read_only=True)
    city = serializers.StringRelatedField(read_only=True)
    district = serializers.StringRelatedField(read_only=True)
    province_id = serializers.IntegerField(label='省ID', required=True)
    city_id = serializers.IntegerField(label='市ID', required=True)
    district_id = serializers.IntegerField(label='区ID', required=True)

    class Meta:
        model = Address
        exclude = ('user', 'is_deleted', 'create_time', 'update_time')

    def validate_mobile(self, value):
        """
        验证手机号
        """
        if not re.match(r'^1[3-9]\d{9}$', value):
            raise serializers.ValidationError('手机号格式错误')
        return value

    def create(self, validated_data):
        """
        保存
        """
        validated_data['user'] = self.context['request'].user
        return super().create(validated_data)


class AddressTitleSerializer(serializers.ModelSerializer):
    """
    地址标题
    """
    class Meta:
        model = Address
        fields = ('title',)

class AddUserBrowseHistorySerializer(serializers.Serializer):
    """添加用户浏览记录的序列化器"""
    # 定义字段sku_id（输入和输出）
    sku_id = serializers.IntegerField(label='商品SKU编号', min_value=1)

    def validate_sku_id(self, value):
        """校验sku_id是否在商品的数目范围内"""
        try:
            SKU.objects.get(id=value)
        except SKU.DoesNotExist:
            raise serializers.ValidationError('sku id 不存在')

        # 如果存在就返回验证后的sku_id
        return value

    def create(self, validated_data):
        """将验证后的sku_id保存到redis数据库"""
        # 获取sku_id
        sku_id = validated_data['sku_id']
        # 获取登录用户的user_id
        user_id = self.context['request'].user.id
        # 获取连接到redis的对象
        redis_conn = get_redis_connection('history')

        # 管道:优化数据的访问效率,实现多条数据的传输
        pl = redis_conn.pipeline()

        # 去重
        pl.lrem('history_%s' % user_id, 0, sku_id)
        # 存储
        pl.lpush('history_%s' % user_id, sku_id)
        # 截取:只截取最前面的五个元素
        pl.ltrim('history_%s' % user_id, 0, 4)

        # 执行
        pl.execute()

        return validated_data